Cyanine dye salts, merocyanine dyes, and their use in silver halide photographic emulsions

ABSTRACT

Silver halide sensitizing dyes of the cyanine salt or merocyanine classes which contain a 3R-imidazole (4, 5-f)quinoline heterocyclic nucleus, and photographic emulsions and elements containing such dyes.

United States Patent Gandino et al.

[451 Sept. 30, 1975 CYANINE DYE SALTS, MEROCYANINE DYES, AND THEIR USE IN SILVER HALIDE PHOTOGRAPHIC EMULSIONS Inventors: Mario Gandino, Ferrania; Luigi Magnani, Carcare, both of Italy Assignee: Minnesota Mining and.

Manufacturing Company, St. Paul,

. Minn.

Filed: Apr. 20, 1972 Appl. No.: 245,795

Related 1.1.5. Application Data [56] References Cited UNITED STATES PATENTS 2,689,849 9/1964 Brooker 96/131 2,743,274 4/1956 Brooker 96/141 3,326,688 6/1967 Jenkins et a1... 96/141 3,431,111 3/1969 Brooker et a1 96/141 Primary Examiner-J. Travis Brown Attorney, Agent, or FirmAlexander, Sell, Steldt & DeLaHunt [5 7 ABSTRACT Silver halide sensitizing dyes of the cyanine salt or merocyanine classes which contain a 3R-imidazole [4, 5-f]-quino1ine heterocyclic nucleus, and photographic emulsions and elements containing such dyes.

13 Claims, N0 Drawings CY ANINE DYE SALTS, MEROCYANINE DYES, AND THEIR USE IN SILVER HALIDE PHOTOGRAPHIC EMULSIONS This is a continuation of application Ser. No. 3,202, filed Jan. 15, 1970, now abandoned.

The present invention relates to cyanine dye salts and merocyanine dyes, and to silver halide photographic emulsions and elements which contain such dyes.

Silver halide compounds in themselves are substantially insensitive to all but the shortest wavelengths of visible light. The sensitivity of silver halide emulsions has been extended to longer wavelengths by incorporation into such emulsions of various sensitizing dyes such as those of the cyanine and merocyanine classes. Such dyes are now routinely used in silver halide emulsions for both black and white and color photography. For example, a photographic element useful for color photography may contain silver halide emulsion layers which have been sensitized respectively to red, green, and blue light. Sensitizing dyes utilized in color photography must accordingly exhibit the required sensitization characteristics, and in addition such dyes must be substantially completely removable from photographic elements during processing so as to impart the least possible sensitizing dye coloration to the final colored image. A summary of sensitizing dye technology and examples of various sensitizing dyesmay be found in Nees and James, The Theory of the Photographic Process, Third Edition, the MacMillan Company, New York, 1966, Chapter 11.

Briefly, the present invention .relates to cyanine dye salts which contain at least two heterocyclic nuclei joined by means of a methine radical or bridge, and to merocyanine dyes. These cyanine dye salts and merocyanine dyes are silver halide sensitizing dyes and are characterized by containing at least one 3-R-ir'nidazo1e [4, -f]-quinoline nucleus. The invention further relates to silver halide photographic emulsions which contain such dyes, as sensitizers, and to photographic elements prepared therefrom.

In its preferred embodiment, the present invention relates to the cyanine dye salts and merocyanine dyes which are characterized respectively by the formulas:

isopropyl, hydroxyethyl, carboxyethyl, etc.; R and R each individually represent an alkyl (including substituted alkyl) group, such as methyl, ethyl, hydroxyethyl, sulfoethyl, carboxyethyl, hydroxypropyl, sulfobutyl, carboxybutyl, phenylmethylene, paracarboxyphenylmethylene, benzothiazole-2-methylene, etc; v Z represent nonmetallic atoms required to complete a 5 or 6 membered heterocyclic ring; X represents an acid radical, preferably a halogen radical; 6 represents nonmetallic atoms required to complete a ketomethylene heterocyclic nucleus; m is O, 1, or 2; and n is 0 or 1.

Exemplary of the 5 or 6 membered heterocyclic rings which are completed by the nonmetallic atoms represented by Z in the above equation I are those of the thiazole series (e.g., thiazole, 4-methyl-thiazole, 4-phenylthiazole, S-methyl-thiazole, S-phenylthiazole, 4,5-

dimethylthiazole, 4,5-diphenylthiazole, etc.); those of the benzothiazole series (e.g., benzothiazole, t-chlorobenzothiazole, 5-chlorobenzothiazole, 6- chlorobenzothiazole, 7-chlorobenzothiazole, 4- methylbenzothiazole, S-methylbenzothiazole, 6- methylbenzothiazole, S-bromobenzothiazole, 6- bromobenzothia zole, 4-phenylbenzothiazole, 5- phenylbenzothiazole, 4-methoxybenzothiazole, 5- methoxybenzothiazole, 6-methoxybenzothiazole, 5- methyl-6-methoxy-benzothiazole, 5- iodobenzothiazole, 6-iodobenzothiazole, 4-ethoxybenzothiazole, S-ethoxy-benzothiazole, 4,5,6,7-tetrahydrobenzothiazole, 5,6-dioxymethylenebenzothiazole, S-hydroxybenzothiazole, 6-hydroxy 4,6-dimethylbenzoxazole, S-methoxybenzoxazole, 6-

In the above formulas (l) and (2): R and R each. individually represent a hydrogen atom, or an alkyl (including substituted alkyl) group, e.g., methyl, ethyl,

methoxybenzoxazole, S-hydroxybenzoxazole, 6- hydroxybenzoxazole, etc.); those of the naphthoxazole series (e.g., [2,1 d]-naphthoxazole, [1, 2 d]- naphthoxazole, etc.); those of the selenazole series (e.g., 4-methylselenazole, 4-phenylselenazole, etc.); those of the benzoselenazole series (e.g., benzoselenazole, 5-chlorobenzoselenazole, 5- methoxybenzoselenazole, 5-hydroxybenzoselenazole, 6-methoxybenzoselenazole, 5,6-dimethoxybenzoselenazole, etc.); those of the naphthoselenazole series (e.g., [1,2 d]-naphthoselenazole, [2,1 d]- naphthoselenazole, etc.); those of the thiazoline series (e.g., thiazoline, 4-methylthiazoline, 4-hydroxymethylthiazoline, 4,4-bis-hydroxymethylthiazoline, 4- acet oxymethyl-4-methylthiazoline, 4,4-bis-acetoxymethylthiazoline, etc.); those of the oxazoline series (e.g., oxazoline, 4-hydroxymethyl-4-methyloxazoline, 4,4- bis-acetoxymethyloxazoline, etc.); those of the selenazoline series; those of the Z-quinoline series (e.g., quinoline, 3-methylquinoline, S-methylquinoline, 7- methylquinoline, 8-methylquinoline, 6- chloroquinoline, 8-chloroquinoline, 6- methoxyquinoline, 6-ethoxyquinoline, 6- hydroxyquinoline, S-hydroxyquinoline, etc.); those of the 4-quinoline series (e.g., quinoline, 6- methoxyquinoline, 7-methoxyquinoline, 8- methylquinoline, etc.); those of the l-isoquinoline series (e.g., isoquinoline, 3,4-diisoquinoline, etc.); those of the 3-isoquinoline series; those of the 3,3- dialkylindolenine series; those of the pyridine series (e.g., pyridine, S-methyl-pyridine, etc.); those of the benzimidazole series (e.g., l-ethylbenzimidazole, lphenylbenzimidazole,

dichlorobenzimidazole, dichlorobenzimidazole,

l-hydroxyethyl-S ,6- l-ethyl-S- chloroben zimidazole, l-ethyl-5-chloro-6- aminobenzimidazole, l-ethyl-S -chloro-6- bromobenzimidazole, l-ethyl-5-acetylbenzimidazole, etc.

Exemplary of the acid radical represented by X in the above equation (1) are such radicals as chloride, bromide, iodide, perchlorate, benzene sulfonate, p-toluene sulfonate, methyl sulfate, ethyl sulfate, propyl sulfate, etc.

Exemplary of ketomethylene heterocyclic nuclei which arecompleted by the atoms represented by G in the above equation (2) are the thiazolone nucleus, for example 2,4-thiazoledione, 3-alkyl-2,4-thiazoledione, (e.g., 3-ethyl-2,4-thiazoledione), 3-phenyl-2,4-' thiazoledione,3-a-naphthyl-Z,4-thiazoledione, etc.; nuclei of the 2-thio-2,4-thiazoledione (rhodanine) type, such as 3-alkyl-2-thio-2,4-thiazoledione (3-alkylrhodanine, e.g., 3-ethyl-2-thio-2,4-thiazoledione), 3- phenyl-rhodanine, 3-a-naphthyl-2-thio-2,4- thiazoledione (i.e., 3-a-naphthyl-rhodanine), 3-(1- benzothiazyl)-2-thio-2,4-thiazoledione (i.e., 3-( l-benzothiazyl )-rhodanine, etc. nuclei of the 2-alkyl-mercapto-4-thiazolone type such as 2-ethylmercapto-4-thiazolone; thiazolidone nuclei such as 4-thiazolidone and 3-alkyl (e.g., ethyl), 3-phenyl or 3- a-naphthyl derivatives thereof; nuclei of the 2-alkylphenylamino-4-thiazolone and 2-diphenylamino-4- thiazolone type; nuclei of the oxazolone type such as a 2-thio-2,4-oxazoledione, (for example a 3-alkyl-2-thio- 2,4-oxazoledione such as 3-ethyl-2-thio-2,4- oxazoledione); nuclei of the 2-imino-2,4-oxazolone type (i.e., pseudo-hydantoin); nuclei of the imidazolone type, such as 2,4-imidazole-dione (hydantoin) or the 3-alkyl(e.g., ethyl), 3-phenyl or 3-a-naphthyl derivatives thereof such as the 1,3-dialkyl (e.g., 1,3-diethyl),

l-alkyl-3-phenyl (e.g., l-ethyl-3-phenyl), l-alkyl-3 oz-naphthyl (eg., l-ethyl-3-a-naphthyl) and 1,3- diphenyl derivatives thereof; nuclei of the 2-thio-2,4- imidazole dione type, for example 2-thio-2,4-imidazole dione (2-thio-hydantoin) and the 3-alkyl (e.g., ethyl), 3-phenyl or B-naphthyl derivatives thereof, such as the l,3-dialkyl (e.g., 1,3-diethyl), l-alkyl-3-phenyl (e.g., l-ethyl-3-phenyl), l-alkyl-3-naphthyl (e.g., l-ethyl-3- naphthyl), and 1,3-diphenyl derivatives thereof; nuclei of the 2-alkylmercapt0-5-imidazolone type such as 2-npropylmercapto-S-imidazolone; nuclei of the 2-thionaphthenone or l-thionaphthenone type; nuclei of the pyrazolone type, oxindole (2,3-dihydroketdindole), 2,- 4,6-triketohexahydropyrimidine (barbituric or thiobarbituric acid) and l-alkyl (for example ethyl) or 1,3- dialkyl (for example 1,3-diethyl) derivatives thereof; nuclei of the 3,4-dihydroquinolone, 3,4- dihydroquinaxalone, 3-phenmorpholone, and l,4,2-benzothiazine-3(4)-one type or like heterocycles having 6 carbon atoms.

The merocyanine dyes and cyanine dye salts of the present invention may be conveniently prepared from quaternary salts of the general formula wherein R, R R and X are as defined above. Such quaternary salts may be obtained by reacting a S-amino benzimidazole with methyl vinyl ketone to give a compound of the formula wherein R and R are as defined above, and then reacting the latter compound with alkyl halides or alkyl esters to provide the formula (3) compounds.

For example, the cyanine dye salts of the present invention may be prepared by condensing a compound of formula (3) with a quaternary salt of the formula I (5) R3I I=(=CHCH=) ID] e) wherein R Z, and X are as defined above, and D represents an alkylmercapto group, a B-arylaminovinyl group, a B-arylmercapto group, a B-arylmercaptovinyl group, a B-acetanilidovinyl group or B-p-toluene sulfoanilido group. This condensation can be advantageously carried out in the presence of a basic condensing agent such as a trialkylamine (e.g., triethylamine), a dialkylaniline, a heterocyclic tertiary amine (e.g.,

pyridine, N-alkyl pyridine) etc. The condensation can also be carried out in the presence of an inert diluent, such as methanol, ethanol, diethylether, acetone, 1,4- dioxane, etc.

The cyanine dye salts of the present invention may also be prepared by condensing an intermediate of the formula f N D (6) xl-l (prepared in a manner analogous to the compound of formula 4) wherein R, R R and are as defined above, with compounds of the formula wherein R X, Z, and n are as defined above. This condensation also may be advantageously carried out in the presence of the previously described basic condensing agents.

Cyanine dye salts of the present invention wherein m equals 1 are preferred and may be conveniently prepared by condensing a compound of the general formula (3) above with an aldehyde of the general frmula wherein Z and R are as defined above. The condensation may be carried out in the presence of an anhydrous inert solvent (e.g., pyridine, a low molecular weight aliphatic alcohol, etc.) and in the presence of a condensing agent such as acetic anhydride, a trialkylamine, an N, N-dialkylaniline, an alkyl piperidine, etc. Temperatures of from about 25C to the boiling temperature of the reaction mixture may conveniently be utilized for this condensation reaction.

Merocyanine dyes of the present invention may be prepared by condensing a quaternary salt of formula (3) with a heterocyclic compound of the formula wherein G is as defined above and E represents an alkyl or aryl mercapto group, an alkoxy group, an arylamino group, an acetanilido group, or a p-toluene sulfanilido group. Similarly, the merocyanine dyes may be prepared by condensing a compound of formula with a compound of the formula EXAMPLE 1 3-ethyl-2,-9-dimethylimidazolo [4, 5-f] quinolinium ethiodide Ferric chloride hexahydrate (398 g.) and zinc chloride 15 g.) were added to 124 g. of 5-amino-l-ethyl-2- methylimidazole in 700 ml. of ethanol. The whole was heated to C and methyl vinyl ketone (129 g.) was added gradually. After 2 hours at C the mixture was refluxed for 4 hours andn was thenallowed to stand overnight. Solvent was then removed by distillation and the residue was basified with 30% sodium hydroxide. The precipitate was filtered, dried, and ether-extracted. 3-Ethyl-2,9 dimethylimidazolo [4, S-f] quinoline (28.3 g., m.p. l76l77C) was recovered from the extract as prisms by recrystallization from ligroin.

Analysis: C H N Calculated 74.7 6.7 l8. Found 74.8 6.8 l8.

The ethiodide was prepared by heating the thus prepared quinoline product at C overnight (sealed tube) with ethyliodide, and was recovered by recrystallization from pyridine. The product (mp 286C) corresponds to the formula The ethiodide of Example 1 (0.38 g.) and 2- (formylmethylidyne)-3-ethyl-5, 6-dimethy] benzothiazole (0.233 g.) were dissolved in 4 ml of pyridine and the solution heated to boiling. Acetic anhydride (0.5 ml) was added and the mixture was refluxed for 5 minutes. The dye which separated out was filtered and washed with hot alcohol and diethyl ether.

Analysis: Found: C% 58.63; H% 5.92% N% 9.45; S% 5.33; 1% 20.40. Calculated: C% 58.44; l-l% 5.58; N% 9.42; S% 5.38; l% 21.15.

The dye obtained corresponds to the formula:

H, n H=CHCH=C l 9 N H3 "C2 N v 1.. Q S

A max 638 mp. in pure ethanol. +1

flit EXAMPLE 3 m- =T CH= H cH=c N 1" The ethiodide of Example 1 (0.38 g.) and 2- c.H. I (formylmethylidyne)-3-ethyl-4, 5- diphenylbenzothiazole (0.3 g.) were dissolved in 2 ml of pyridine and the solution heated to boiling. Acetic N anhydride (0.3 ml) was added, and the mixture was refluxed and was permitted to stand overnight at 0C. 2 5 The dye obtained was filtered, washed with diethyl ether and crystallized from ethanol. EXAMPLE 5 Analysis: Found: C% 61.85; H% 5.36; N% The ethiodide of Example 1 (0.76 g.) and 0.506 g. of 8.25; S% 4.78; l% 19.50. Calculated: C% 62.74; 2-(formylmethylidyne)-3-ethyl-5-methoxy benzoselen- H% 5.27; N% 8.36; S% 4.79; 1% 18.94. azole were dissolved in 3 ml of pyridine and the solu- The dye obtained exhibited maximum absorption at tion was heated to boiling. Then 0.4 ml of acetic anhy- 655 my. (in pure ethanol) and corresponded to the fordride were added and the mixture was refluxed for l mula: minute. The dye separated out immediately and was filtered and washed with boiling water and diethyl ether. The dye exhibited maximum absorption at 633 mu (in pure ethanol) and corresponded to the formula:

SK (+I CH -,C=N CH=CH-CH=C ocH, l H C l\k N bl z s G (+1 EXAMPLE 6 11 The ethiodide of Example 1 (0.38 g.) and 0.255 g. of CH3C=N CH=CH-CH=C Q Z-(formylmethylidyne )-3-ethyl-B-naphthothiazole C2H5 N were dissolved in 5 ml of pyridine and the solution was l heated to boiling. Then 0.5 ml of acetic anhydride were C H added and the mixture was refluxed for 2 minutes, dur- 2 5 ing which time the dye separated out. The mixture was N cooled and the dye product was filtered and washed l with boiling water, alcohol and ether. The dye exhib- CZH ited maximum asorption at 649 my. and corresponded to the formula:

. /s cH..c=r -1 cH-cH=c\ H H C 111 N b a EXAMPLE 4 EXAMPLE 7 The ethiodide of Example 1 (0.38 g.) and 0.21 g. of 2-(formylmethylidyne)-3, 6-dimethylbenzothiazole were dissolved in 5 ml of pyridine and the solution was heated to boiling. Then 0.5 ml of acetic anhydride were added and the mixture was refluxed for'l minute. The dye product was filtered and washed with hot alcohol and diethyl ether. The dye exhibited maximum absorption at 631 mp. (in pure ethanol) and corresponded to the formula:

The ethiodide of Example 1 (0.76 g.) and 0.214 g. of 2-( formylmethylidyne)-3 -ethyl thiazoline were dissolved in 3 ml of pyridine and the solution was heated to boiling. Then, 0.4 ml of acetic anhydride were added and the mixture was refluxed for 5 minutes. After standing overnight the dye separated out. The dye product was, filtered, washed with alcohol-ether and crystallized from pyridine. The dye exhibited maximum absorption 'at 576 my. (in pure ethanol) and corresponded to the formula:

The ethiodide of Example 1 (0.76 g.) and 0.674 g. of Z-methyl-mercapto=benzothiazole ethiodide in 20 ml of absolute ethanol were heated to boiling. Triethylamine (2 ml) were added and the mixture was refluxed for 10 minutes. The dye which separated out was filtered and washed with alcohol and ether. The product was further purified by boiling in acetic acid and in ethanol The dye exhibited maximum absorption at 501 my. (in pure ethanol) and corresponded to'the formula:

10-) N CH=C /N\ i i c n c n T c n,

EXAMPLE 9 The ethiodide of Example 1 (0.76 g.) and 0.57 g. of 2-methyl-mercapto-4-methylthiazole methiodide in 20 ml of absolute ethanol were heated to boiling. Then 2 ml of triethylamine were added and the mixture was refluxed for 1 /2 hours, during which time the dye product separated as a brick red colored precipitate. The dye was cooled and filtered, washed with hot water, warm alcohol and diethyl ether. The dye exhibited maximum absorption at 506 my. (in pure ethanol) and corresponded to the formula:

fin CH -C=N CH A: /CCH;, H C N N N l C H EXAMPLE 10 The ethiodide of Example 1 (0.76 g.) and 0.718 g. of

2-ethyl-mercapto--methyl-quinoline ethiodide were heated to boiling in ml of absolute ethanol. The 2 ml of triethylamine were added and boiling was continued for one-half hour. The color of the solution was violet red. The solution was left standing for 2 hours and the dye separated out in the form of golden green plates. The dye was then washed with hot water, warm alcohol and diethyl ether. The dye exhibited maximum absorption at 565 my. (in pure ethanol) and corresponded to the formula:

The ethiodide of Example 1 (0.76 g.) and 0.65 g. of 2-ethylmercapto-6,7-dimethylquinoline ethyl bromide were heated to boiling in 30 ml of ethanol. Then 3 ml of triethylamine were added and the mixture was refluxed for 15 minutes. On cooling, golden green crystals separated out. The dye product was filtered and washed with hot water, warm alcohol and diethyl ether.

The dye exhibited maximum absorption at 567 mp.

(in pure ethanol) and corresponded to the formula:

N CH3 I CZHJ EXAMPLE 12 The ethiodide of Example 1 (0.76 g.) and 0.84 g. of acetanilidovinylbenzoxazole methiodide were heated to boiling in 30 ml of absolute ethanol. Then 3 ml of triethylamine were added and the mixture was refluxed for three-fourths hour. On cooling, the dye separated out. The dye was filtered, washed with hot water, alcohol and ether, and was crystallized from pyridine. The dye exhibited maximum absorption at 590 mu (in pure ethanol) and corresponded to the formula:

EXAMPLE 13 The ethiodide of Example 1 (0.76 g.) and 0.89 g. of 2-acetanilidovinyl-5,6-dimethylbenzoxazole ethiodide in 30 ml of absolute ethanol were heated to boiling. Then 3 ml of triethylamine were added and the mixture was refluxed for minutes, during which period the dye separated out. The dye was filtered, washed with hot water, alcohol and ether, and was crystallized from ethanol. The dye exhibited maximum absorption at 602 mu (in pure ethanol) and corresponded to the formula:

The ethiodide of Example 1 (0.76 g.) and 0.58 g. of 5-acetanilino-methylene-3-ethyl-oxazolidone were heated to boiling in 30 ml of absolute ethanol. Then 3 ml of triethylamine were added and the mixture was refluxed for 2 hours. After standing overnight, the dye separated out. The dye was washed with hot water, alcoho], and ether, and was crystallized from pyridine. The dye exhibited maximum absorption at 604 my. (in pure ethanol) and corresponded to the formula:

EXAMPLE or halides. In addition, such emulsions may contain various other ingredients commonly used in the photographic art, such as other spectral sensitizers, chemical sensitizers, supersensitizers, antifoggants, stabilizers, surfactants, couplers, etc. The emulsions may be spread on a variety of substrates such as cellulose triacetate films, polyester films, glass, paper, and the like.

The following illustrative example shows a preferred embodiment of photographic elements of the present invention.

EXAMPLE 16 The sensitizing dye of Example 2 was added to a gelatino-silver halide photographic emulsion containing 91.5 mol% of AgCl and 8.5 mol% of AgBr. The resulting emulsion was spread on a cellulose triacetate base which was then dried and exposed on a Zeiss spectograph and developed for 13 minutes at 20C in a color developer of the p-phenylene diamine type. The emulsion showed significant spectral sensitization in the 650 mp. area of the spectrum.

We claim:

1. A silver halide photographic emulsion containing a sensitizing dye of the formula The ethiodide of Example 1 (0.38 g.) and 0.31 g. of

5-acetanilino-methylene-3-ethyl rhodanine were heated to boiling in 30 ml of absolute ethanol. Then 3 ml of triethylamine were added and the mixture was refluxed for 10 minutes. The goldengreen dye crystals which were obtained from the hot mixture were filtered and washed with hot water, alcohol and ether. The dye exhibited maximum absorption at 627 my (in pure ethanol) and corresponded to the formula H C -N bin,

The cyanine dye salts and the merocyanine dyes of the present invention may be introduced in sensitizing amounts into silver halide photographic emulsions by methods well known to those skilled in the art. Such emulsions commonly include natural and/or synthetic colloids permeable to aqueous media, and silver halide,

a CH-am (L D wherein R and R each individually represent a hydrogen atom or an alkyl group; R and R each individually represent an alkyl group; m is 0, l, or 2; n is 0 or 1; Z represents the atoms necessary to complete a 5 or 6 membered heterocyclic ring; X represents an acid radi- 5 cal; and D represents atoms required to complete a ketomethylene heterocyclic nucleus having a 5 or 6 membered heterocyclic ring.

2. A silver halide photographic emulsion containing a sensitizing dye of the formula a N N L (his.

Q a a I wherein R and R each individually represent a hydro- 7. The silver halide photographic emulsion of claim gen atom or an alkyl group; R and R each individually 1 wherein said dye is characterized by the formula represent an alkyl group; m is O, l, or 2; n is O or 1; Z represents the atoms necessary to complete a 5 or 6 1+) membered heterocyclic ring; and X represents an acid H radical. l

3. The photographic emulsion of claim 1 wherein said dye is characterized by the formula (4-) 1-1 8. The silver halide photographic emulsion of claim 1 wherein said dye is characterized by the formula H C N CH=CH-CH H5C ,N N/ CH3 I r cH3 C H c S CH i N N H=CHCH=C\ l c H NcH b r-1 2 5 l C H 4. The photographic emulsion of claim 1 wherein N said dye is characterized by the formula 9. The silver halide photographic emulsion 0f claim W 1 wherein said dye is characterized by the formula l 40 CH -i'- N CH=CHCH c- H CH -z s \C S 2 5 N N CH=C I 2 5 N T l s u C2H5.

T 5. The photographic emulsion of claim 1 wherein said dye is characterized by the formula d 10. The silver halide photographic emulsion of claim CH 1 wherein said (1 e is characterized b the formula cHJic=N CH=CH-CH=C/S/ 1 y y C l-l N It) T C2145.

6. The photographic emulsion of claim 1 wherein said dye is characterized by the formula 11. The silver halide photographic emulsion of claim y CH3 1 wherein said dye is characterized by the formula; I

CH IN I() 5 0,14 CH:

l CH,,C=N CH= N F" 13. The silver halide photographic emulsion of claim 1 wherein said dye is characterized by the formula H c. -N v I o 5 z s CH;C=N CH=C HCH s 2 I Tl I) CH pl a C H 1 C l-l 12. The silver halide photographic emulsion of claim 1 wherein said dye is characterized by the formula UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,909, 75 9 DATED September 3 1975 INVENTOR(S) Mario Gandino and Luigi Magnani It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Or Col. 6', line 65, "5.92%" should be 5.92;

col. '4, first dia ram, R c H) n g N \N on x 3 1 or should be 11 7 /N N CH3 x 0 1 N/ I R2 Q Page 2 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,909,275 0 DATED September 30, 1975 |NVENTOR(S) Mario Gandino and Luigi Magnani It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

. 001. l, second diagram 4), R C I should be R Page 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 1 3,909,275 DATED September 3 975 |NVENTOR(S) Mario Gandino and Luigi Magnani it is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

C010 8, third diagram (Example 6) S CHC=N CH-CH=C t 3 H C N N 5 2 should be w Inl- CH C=N CH=CH-CH=C N Q 5 2 N I 2 5 N (L H 2 5 Signed and Scaled this sixth D y of January 1976 [SEAL] Arrest:

O RUTH c. MASON C. MARSHALL DANN Arresting Officer Commissioner ufPaIenrs and Trademarks 

1. A SILVER HALIDE PHOTOGRAPIC EMULSION CONTAINING A SENSITIZING DYE OF THE FORMULA
 2. A silver halide photographic emulsion containing a sensitizing dye of the formula
 3. The photographic emulsion of claim 1 wherein said dye is characterized by the formula
 4. The photographic emulsion of claim 1 wherein said dye is characterized by the formula
 5. The photographic emulsion of claim 1 wherein said dye is characterized by the formula
 6. The photographic emulsion of claim 1 wherein said dye is characterized by the formula
 7. The silver halide photographic emulsion of claim 1 wherein said dye is characterized by the formula
 8. The silver halide photographic emulsion of claim 1 wherein said dye is characterized by the formula
 9. The silver halide photographic emulsion of claim 1 wherein said dye is characterized by the formula
 10. The silver halide photographic emulsion of claim 1 wherein said dye is characterized by the formula
 11. The silver halide photographic emulsion of claim 1 wherein said dye is characterized by the formula
 12. The silver halide photographic emulsion of claim 1 wherein said dye is characterized by the formula
 13. The silver halide photographic emulsion of claim 1 wherein said dye is characterized by the formula 